Moving Charges and Magnetism — Physics STD 12 Science — Question

X-ray incident on a material:

1. Exerts a force on it.
2. Transfers energy to it.
3. Transfers momentum to it.
4. Transfers impulse to it.

Which of the following phenomena can be demonstrated by light. But not with sound waves in an air column? 

Wave front means:

The value of yellow colour in colour code in carbon resistance :

Which of the following is true for number of spectral lines in going form Layman series to Pfund series

(a) Increases	(b) Decreases
(c) Unchanged	(d) May decreases or increases

A count rate meter shows a count of 240 per minute from a given radioactive source. One hour later the meter shows a count rate of 30 per minute. The half-life of the source is

(a) 120 min

(b) 80 min

(c) 30 min

(d) 20 min

The ratio of de-Broglie wavelengths of molecules of hydrogen and helium which are at temperature 27^oC and 127^oC respectively is

(a)

(b)

(c)

(d) 1

Mark out the correct options.

1. Diamagnetism occurs in all materials.
2. Diamagnetism results from the partial alignment of permanent magnetic moment.
3. The magnetizing field intensity H is always zero in free space.
4. The magnetic field of induced magnetic moment is opposite to the applied field.

I-V characteristic of a copper wire of length L and area of cross-section A is shown in figure.  The slope of the curve becomes

(a) More if the experiment is performed at higher temperature

(b) More if a wire of steel of same dimension is used

(c) More if the length of the wire is increased

(d) Less if the length of the wire is increased